Sleep quality relates to health of individuals. A wearable device can be used to record activity amount of a user to determine a sleep state of the user, and evaluate sleep quality of the user using the sleep state. Some microactivities of the user before or after sleep (e.g., reading, using a cell phone, etc.) are similar to those in the sleep state. Although an activity amount can be used to determine the sleep state, the microactivities of the user often cannot be accurately recognized, which can affect monitoring the sleep quality of the user.